Electrical contact-terminal assembly

ABSTRACT

THE SHANK OF AN ELECTRICAL CONTACT RIVET FOR AN ELECTRICAL SWITCH IS FORMED WITH AN INTERMEDIATE SPLINED PORTION, THE MAJOR DIAMETER OF WHICH IS GREATER THAN EITHER THE SHANK OR THE COOPERATING TERMINAL OPENING. THE SPLINED PORTION IS UPSET WHEN THE TERMINAL IS DRIVEN UPON THE   SHANK TO FORM A SEAT AGAINST WHICH THE TERMINAL IS SUBSEQUENTLY RIVETED TO FORM A GOOD ELECTRICAL AND MECHANICAL CONNECTION IRRESPECTIVE OF ANY OTHER ELEMENT.

' Feb. 9, 1971 r R. G. ILLER 3,562,700

ELECTRICAL CONTACTrTERMINAL ASSEMBLY Filed Sept. 29, 1969 2 Sheets-Sheet 1 jig. 1

Inventor Ricfiard 9.Mil'/Er By 5! K- M fittomey Feb. 9, 1971 Filed Sept. 29, 1969 R. G, MILLER ELECTRICAL CONTACT-TERMINAL ASSEMBLY 2 Sheets-Sheet 2 I nven tar Ricfiard 9.Mil'l?r United States Patent Office 3,562,700 Patented Feb. 9, 1971 3,562 700 ELECTRICAL CONTACT- TERMINAL ASSEMBLY Richard G. Miller, Milwaukee, Wis., assignor to Cutler- Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Filed Sept. 29, 1969, Ser. No. 861,872 Int. Cl. H01r 9/14, /08

US. Cl. 339-220 3 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to electrical contact-terminal rivet connections for switches and the like. More particularly, this invention relates to contact-terminal assemblies which extend through insulating housings or the like.

A commonly employed method of securing a terminal member to a contact is to form the contact into a rivet, pass the shank thereof through an opening in the housing and through the terminal and upset the protruding end over the terminal to rivet the latter tightly against the housing. The mechanical connection may break down if the housing is damaged or shrinks, thereby creating a loose and faulty electrical connection.

SUMMARY OF THE INVENTION It is the primary object of this invention to provide an electrical contact-terminal connection which will remain firm irrespective of the condition of the mounting base.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing the contact structure of this invention incorporated in an exemplary switch;

FIG. 2 is a side elevational view of the contact member of this invention;

FIG. 3 is an isometric view of the contact member and a cooperating terminal member therefor;

FIG. 4 is a view showing the terminal member in a first step as it is applied to the contact; and

FIG. 5 is a view showing a second step wherein the contact is riveted over the terminal member.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of the drawings, the contact structure of this invention is illustrated with a positive break, toggle lever electrical switch of a type commonly employed in aircraft. A more complete description of the switch may be had from US. Pat. No. 3,035,134 to H. W. Hults and assigned to the assignee herein.

The switch comprises a molded insulating base 2 upon which the various contacts and switching structure are assembled, and a metallic housing, or cover 4 clamped to the base 2 by tabs (not shown). Housing 4 is provided with an upstanding threaded bushing 6 which is used for mounting the switch to a panel. An operating lever 8 is pivotally mounted upon a pivot pin 10 which extends transversely through the bushing 6.

Molded insulating base 2 is provided with a central substantially rectangular cavity 12 open to the upper side thereof. The bottom wall of the cavity 12 is provided with three holes extending to the exterior of base 2 and through which three contact rivets 14, 14 and 16 extend. L-shaped terminal members 18 are riveted to each of the contacts 14, 14 and 16 at the exterior of base 2 in a manner to be described more fully in later description.

Central contact 16 has a spherical recess formed in the upper surface of the head portion thereof to receive a spherical end portion 20 of a driver element 22. The latter has a spherical end 24 opposite the end 20 which connects to the inner end of lever 8 through an operating mechanism (not shown). Supported on the driver element 22 is a rocking type bridging contactor 26 which has a central aperture through which the upper portion of driver element 22 projects. A conical compression spring 28 bears upon the bridging contactor 26 to maintain the latter against the driver element. Movement of lever 8 will effect movement of driver element 22 through the operating mechanism to rock the contactor into engagement with either the right or left-hand contact 14, thereby electrically bridging the latter to the center contact 16.

A commonly practiced method of performing the electrical and mechanical connection of the contacts 14, 14 and 16 is to rivet the terminal tightly against the base 2. Elastic sealing rings 30 are placed around the shanks of the contacts adjacent the heads thereof to hermetically seal off the apertures. One problem in this method results when the insulating base weakens, shrinks, or cracks. The mechanical connection between the terminal 18 and respective contact 14 or 16 becomes loose and the electrical connection therebetween fails.

With reference to FIGS. 2 and 3, the contacts 14, and similarly contact 16, have been provided with a toothed, splined portion 32 on the shank intermediate the ends of the shank. The major diameter of splined portion 3-2 is greater than the diameter of the shank portion 34 or the corresponding hole 36 in terminal member 18. Thus, when the terminal is driven upon the shank of the contact, the interfering edges of the splines are peeled or forced upwardly toward the head portion to form an upper seat for the terminal 18. When the protruding portion of the shank 34 is riveted over the outside of terminal 18, a strong electrical and mechanical connection is provided therebetween which will continue to exist regardless of the condition of base 2.

I claim:

1. A terminal assembly for an electrical enclosure comprising, in combination:

an insulating base for said enclosure;

a hole through said base;

an electrically conductive cylindrical rivet member extending through said hole in said base and having a splined portion on the shank thereof protruding beyond the exterior surface of said base, said splined portion having a major diameter greater than the diameter of said shank portion; and

an electrical terminal member having an aperture therein of a diameter greater than the shank diameter and less than said major diameter of said splined portion, said terminal member being forced onto said rivet member to peel back the outer portions of said splines to form a seat against which the terminal is riveted by upsetting the portion of said rivet protruding through said aperture over the exterior surface of said terminal. 2. The combination according to claim 1 together with a portion of said shank extending beyond said splined portion.

3. An electrical contact-terminal assembly for an enclosed electric switch comprising, in combination:

an insulating base for said switch; a hole through said base; an electrically conductive cylindrical rivet member extending through said hole in said base, said rivet having a contact head portion abutting against the interior surface of said base and a splined portion on the shank thereof protruding beyond the exterior surface of said base, said splined portion having a major diameter greater than the diameter of said shank portion; and

an electrical terminal member having an aperture therein of a diameter greater than the shank diameter and less than said major diameter of said splined portion, said terminal member being forced onto said rivet member to peel back the outer portions of said splines to form a seat against which the terminal is riveted by upsetting the portion of said rivet protruding through said aperture over the exterior surface of said terminal.

References Cited UNITED STATES PATENTS 10 MARVIN A. CHAMPION, Primary Examiner R. A. HAFER, Assistant Examiner US. Cl. X.R. 

